The present invention relates to a pyrolysis/drying system, particularly for pyrolysing/drying biological sludge, on which the material is heated indirectly by means of hot fumes inside a rotary furnace through which the material is fed in a continuous stream.
On pyrolysis/drying systems currently available on the market, the material is known to be processed mainly by direct heating. When the consistency of the material being processed is such that continuous processing requires the use of a rotary furnace, direct heating is the only economical solution from the systems standpoint, even in cases where, from the purely processing standpoint, indirect heating would be preferable, e.g. to prevent ruining the material and/or for enabling the recovery of any gases given off by the same. Indirect heating, however, involves too great an outlay in terms of connecting devices between the furnace and the rest of the system, due to the difficulty encountered in ensuring the necessary sealing of mutually mobile fittings.